New negative metallic electrode for solid batteries with a solid protonic conductor (SPC) as electrolyte

The proposed negative metallic composite electrode has the benefits of the low potential of a metal/metal ion system such as Zn/Zn 2+ and of the high protonic transport number in a SPC, while exhibiting good discharge power and energy densities. In this electrode, the metal powder and a SPC are mixed with compounds able to exchange protons with the SPC and also metal ions with the metal. In a first electrode-forming method, this compound is obtained by a preanodization of the metal in aqueous electrolyte before pressing it with the SPC; in a second method the metal is mixed and pressed with various hydrated salts. The electrochemical behavior was tested; these electrodes have then been combined with a SPC layer and a positive composite electrode. The characteristics obtained are very interesting for “all solid” batteries working at room temperature. These cells are stable in presence of air. In all cases, the SPC is HUP; the negative metal is Zn or Pb; the positive material is PbO 2 or MnO 2 .